An eighth of it is 0.0295735 liter.
Only if you have pure water you can say:
0.0295735 liter weighs 0.0295735 kilograms.
That is 29.5735 grams.
205 grams
A half-cup of tofu is approximately 4 oz by weight - as per http://vegetarian.about.com/od/healthnutrition/p/tofunutrition.htm
3.5 grams = 1/8th oz
1 cup = 226,79 grams / 226,79 grams = 1 cup
I believe there are 3 teaspoons to 1 tablespoon and 4 tablespoons to 1/4 cup That would make 48 teaspoons to 1 cup if my mathematics are right